A new leaked document has cast doubt over the Copenhagen climate change
conference just as President Barack Obama arrived.

More than 110 world leaders have gathered in Copenhagen to fight global warming.

However, as the talks draw to a close, there was growing anger at failure to reach an agreement. Differences between rich and poor countries are still so great that Mr Obama was forced to delay his schedule and hold further talks with 19 other world leaders to try and work out the agreement.

At the same time a draft document was leaked that would ask the world to keep temperature rise below 2C (3.6F).

It would ask rich countries to cut greenhouse gases, but does not yet have legally-binding numerical targets. It would also ask developing countries to take action to reduce emissions for the first time.

The leaked text caused anger among delegates just as President Obama arrived at the conference to “save the Earth”.

A source, who is close to the negotiations, said the world will be unable to keep dangerous global warming within safe limits without legally-binding targets for the rich countries.

“What is on the table is not enough to save the Earth. The Earth is going to burn with what is on the offer here. We have one chance to get it right. We have a decade to get emissions under control. If we do not get it right now it is not just a catastrophe in terms of the negotiations, it is a catastrophe in terms of people’s lives.”

It is understood the leaked document was circulating last night as negotiators struggle to draw up an agreement that world leaders can sign by the end of today.

Throughout the negotiations a number of documents, including a “Danish text”, have been leaked, sparking anger among delegates.

However the final outcome of the two-week talks is still uncertain. It is expected world leaders will sign up to a political declaration that will commit the world to keeping temperatures below 2C and cutting emissions. It is also likely to offer the developing world $100bn (£60bn) by 2020 to cut emissions and adapt to climate change.

Downing Street sources were still optimistic on Thursday that a political deal will still be done.

The sticking point is over how emissions reductions by the developing world will be measured, after the Chinese expressed concern for “national sovereignty”.

Whatever is decided it will only be a political declaration as delegates have been unable to agree on the details.

A final legal treaty is unlikely to be signed until six months to a year’s time when world leaders will meet again in Mexico